[User-mode-linux-devel] Re: 2.3.51 panic - probable answer

> One more note; the same Kernel panic showed up when I was slowly
> filling up 24M of uml memory with executing bash over and over again.
> It seems that the hard drive space shrunk (perhaps as the memory used
> by uml grew?), and it seemed as if UML panic'ed right about the time,
> ahem, I ran out of disk space.
What I think is going on is that the hosting kernel only allocates memory (and
disk space, since the memory is housed in an mmaped file) as the uml touches
it. When a disk or memory allocation fails, the uml suddenly finds that
memory that it thought it had doesn't exist any more.
I've thought about this a bit more, and I think I'm going to consider it as
equivalent to bad hardware, like a native kernel discovering that it has a
bank of bad memory. The native kernel will panic, and the lkml crowd will
tell you to go away and replace your memory.
I'll see if I can come up with some better diagnostics, though.
Jeff

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> One more note; the same Kernel panic showed up when I was slowly
> filling up 24M of uml memory with executing bash over and over again.
> It seems that the hard drive space shrunk (perhaps as the memory used
> by uml grew?), and it seemed as if UML panic'ed right about the time,
> ahem, I ran out of disk space.
What I think is going on is that the hosting kernel only allocates memory (and
disk space, since the memory is housed in an mmaped file) as the uml touches
it. When a disk or memory allocation fails, the uml suddenly finds that
memory that it thought it had doesn't exist any more.
I've thought about this a bit more, and I think I'm going to consider it as
equivalent to bad hardware, like a native kernel discovering that it has a
bank of bad memory. The native kernel will panic, and the lkml crowd will
tell you to go away and replace your memory.
I'll see if I can come up with some better diagnostics, though.
Jeff